U.S. patent application number 17/193783 was filed with the patent office on 2021-09-09 for micro-optic for micro-led projection unit.
This patent application is currently assigned to LUMILEDS HOLDING B.V.. The applicant listed for this patent is LUMILEDS HOLDING B.V.. Invention is credited to Benno SPINGER, Steffen ZOZGORNIK.
Application Number | 20210278055 17/193783 |
Document ID | / |
Family ID | 1000005465039 |
Filed Date | 2021-09-09 |
United States Patent
Application |
20210278055 |
Kind Code |
A1 |
SPINGER; Benno ; et
al. |
September 9, 2021 |
MICRO-OPTIC FOR MICRO-LED PROJECTION UNIT
Abstract
A lighting device is described. The lighting device includes at
least one first arrangement of light emitting elements and at least
one second arrangement of light emitting elements spatially
separated from the at least one first arrangement of light emitting
elements. The lighting device also includes at least one first
magnifying optical element arranged in correspondence with the at
least one first arrangement of light emitting elements and at least
one second magnifying optical element arranged in correspondence
with the at least one second arrangement of light emitting
elements. At least one optical projection element is arranged and
configured to generate a combined image of a magnified image of the
at least one first arrangement of light emitting elements and a
magnified image of the at least one second arrangement of light
emitting elements.
Inventors: |
SPINGER; Benno; (Aachen,
DE) ; ZOZGORNIK; Steffen; (Leverkusen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LUMILEDS HOLDING B.V. |
Schiphol |
|
NL |
|
|
Assignee: |
LUMILEDS HOLDING B.V.
Schiphol
NL
|
Family ID: |
1000005465039 |
Appl. No.: |
17/193783 |
Filed: |
March 5, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21Y 2115/10 20160801;
F21S 41/275 20180101; G02B 27/30 20130101; G02B 27/1066
20130101 |
International
Class: |
F21S 41/275 20060101
F21S041/275; G02B 27/30 20060101 G02B027/30; G02B 27/10 20060101
G02B027/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 5, 2020 |
EP |
20161097.9 |
Claims
1. A lighting device comprising: at least one first arrangement of
light emitting elements; at least one second arrangement of light
emitting elements spatially separated from the at least one first
arrangement of light emitting elements; at least one first
magnifying optical element arranged in correspondence with the at
least one first arrangement of light emitting elements; at least
one second magnifying optical element arranged in correspondence
with the at least one second arrangement of light emitting
elements; and at least one optical projection element arranged and
configured to generate a combined image of a magnified image of the
at least one first arrangement of light emitting elements and a
magnified image of the at least one second arrangement of light
emitting elements.
2. The lighting device of claim 1, wherein the at least one first
magnifying optical element is arranged and configured to generate
the magnified image of the at least one first arrangement) of light
emitting elements, and wherein the at least one second magnifying
optical element is arranged and configured to generate a magnified
image of the at least one second arrangement (10) of light emitting
elements.
3. The lighting device according to claim 1, further comprising: at
least one first arrangement of optical collimation elements, each
of the optical collimation elements of the at least one first
arrangement of optical collimation elements is arranged in
correspondence with a corresponding on of the light emitting
elements of the at least one first arrangement of light emitting
elements; and at least one second arrangement of optical
collimation elements, wherein each of the optical collimation
elements of the at least one second arrangement of optical
collimation elements is arranged in correspondence with a
corresponding one of the light emitting elements of the at least
one second arrangement of light emitting elements.
4. The lighting device according to claim 3, wherein each of the
optical collimation elements of the at least one first arrangement
of optical collimation elements and the at one second arrangement
of optical collimation elements comprises a lens element arranged
to collimate light emitted from the corresponding one of the light
emitting elements.
5. The lighting device according to claim 3, wherein the at least
one first magnifying optical element, the at least one second
magnifying optical element and the optical collimation elements of
the at least one first arrangement of optical collimation elements
and the at one second arrangement of optical collimation elements
are integrally formed.
6. The lighting device according to claim 3, further comprising an
optical member arranged in a path of light emitted from light
emitting elements of the first and the second arrangement of light
emitting elements, the first magnifying optical element and the
second magnifying optical element forming a face of the optical
member facing away from the first and the second arrangement of
light emitting elements, and the at least one first arrangement of
optical collimation elements and the at least one second
arrangement of optical collimation elements forming a face of the
optical member facing the first and the second arrangement of light
emitting elements.
7. The lighting device according to claim 3, wherein the light
emitting elements respectively correspond to micro-LEDs, and
wherein the at least one first arrangement of optical collimation
elements and the at least one second arrangement of optical
collimation elements respectively correspond to respective
arrangements of micro-lenses.
8. The lighting device according to claim 1, wherein at least one
of the at least one first magnifying optical element, the at least
one second magnifying optical element, at least one of the optical
collimation elements, or the optical member comprises glass or
silicone.
9. The lighting device according to claim 1, wherein the at least
one second arrangement of light emitting elements is spatially
separated from the at least one first arrangement of light emitting
elements by a gap having a width that is larger than a width of a
gap separating a first light emitting element of the at least one
first arrangement.
10. The lighting device according to claim 1, wherein the at least
one second arrangement of light emitting elements is spatially
separated from the at least one first arrangement of light emitting
elements by a gap having a width that is larger than a width of a
gap separating the at least one second arrangement from a second
light emitting element of the at least one first arrangement.
11. The lighting device according to claim 1, wherein the at least
one second arrangement of light emitting elements is spatially
separated from the at least one first arrangement of light emitting
elements by a gap having a width that is larger than a width of a
gap separating the at least one second arrangement arranged
adjacent to the first light emitting element.
12. The lighting device according to claim 1, wherein the light
emitting elements of at least one of the at least one first
arrangement of light emitting elements or the at least one second
arrangement of light emitting elements are configured to be at
least one of individually addressable or addressable in groups.
13. The lighting device according to claim 1, wherein at least one
of the at least one first arrangement of light emitting elements or
the at least one second arrangement of light emitting elements is a
matrix arrangement of the light emitting elements.
14. The lighting device according to claim 1, wherein a focus of
the at least one optical projection element is in a plane defined
by at least one of the at least one first arrangement of light
emitting elements or the at least one second arrangement of light
emitting elements.
15. The lighting device according to claim 1, wherein the at least
one optical projection element comprises a single lens or a lens
system arranged to collect light emitted from all of the light
emitting elements of the at least one first and the at least one
second arrangement of light emitting elements.
16. The lighting device according to claim 1, wherein the light
emitting elements are light emitting diodes (LEDs).
17. A lighting system comprising: a lighting device comprising: at
least one first arrangement of light emitting elements, at least
one second arrangement of light emitting elements spatially
separated from the at least one first arrangement of light emitting
elements, at least one first magnifying optical element arranged in
correspondence with the at least one first arrangement of light
emitting elements, at least one second magnifying optical element
arranged in correspondence with the at least one second arrangement
of light emitting elements, and at least one optical projection
element arranged and configured to generate a combined image of a
magnified image of the at least one first arrangement of light
emitting elements and a magnified image of the at least one second
arrangement of light emitting elements; and a controller configured
to individually control at least one of the light emitting elements
of the at least one first arrangement or the lighting elements of
the at least one second arrangement of light emitting elements.
18. The lighting system according to claim 17, wherein the lighting
system is an automotive headlight system.
19. The lighting system according to claim 17, wherein the at least
one first magnifying optical element is arranged and configured to
generate the magnified image of the at least one first arrangement)
of light emitting elements, and wherein the at least one second
magnifying optical element is arranged and configured to generate a
magnified image of the at least one second arrangement (10) of
light emitting elements.
20. The lighting system according to claim 17, wherein the lighting
device further comprises: at least one first arrangement of optical
collimation elements, each of the optical collimation elements of
the at least one first arrangement of optical collimation elements
is arranged in correspondence with a corresponding on of the light
emitting elements of the at least one first arrangement of light
emitting elements, and at least one second arrangement of optical
collimation elements, wherein each of the optical collimation
elements of the at least one second arrangement of optical
collimation elements is arranged in correspondence with a
corresponding one of the light emitting elements of the at least
one second arrangement of light emitting elements.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of EP Application
20161097.9, filed Mar. 5, 2020, which is incorporated by reference
as if fully set forth.
FIELD OF INVENTION
[0002] The present disclosure relates to a lighting device
comprising at least first and second arrangements of light emitting
elements, in particular micro-LEDs, and optical elements.
BACKGROUND
[0003] Lighting devices comprising arrangements of light emitting
elements such as matrix light emitting dine (LED) arrangements have
become advantageous for projector applications in general and for
automotive applications, such as for automotive headlight
applications. Automotive applications may include, for example,
Adaptive Driving Beam (ADB) applications, Low Beam, High Beam, and
Adaptive Front-lighting System applications.
[0004] Thereby, micro-LEDs have become advantageous light sources
as they may enable placing individual LEDs as pixels at high
spatial density and thus may enable projecting images with sharply
defined edges and high contrast.
SUMMARY
[0005] A lighting device is described. The lighting device includes
at least one first arrangement of light emitting elements and at
least one second arrangement of light emitting elements spatially
separated from the at least one first arrangement of light emitting
elements. The lighting device also includes at least one first
magnifying optical element arranged in correspondence with the at
least one first arrangement of light emitting elements and at least
one second magnifying optical element arranged in correspondence
with the at least one second arrangement of light emitting
elements. At least one optical projection element is arranged and
configured to generate a combined image of a magnified image of the
at least one first arrangement of light emitting elements and a
magnified image of the at least one second arrangement of light
emitting elements.
BRIEF DESCRIPTION OF THE DRAWING
[0006] A more detailed understanding can be had from the following
description, given by way of example in conjunction with the
accompanying drawings wherein:
[0007] FIG. 1A is a top view of an example LED array;
[0008] FIG. 1B is a side view of an example lighting device;
[0009] FIG. 2 is a perspective view of example magnifying optical
elements and optical collimation elements;
[0010] FIG. 3A illustrates an example result of a numerical
simulation of a light distribution emitted from a lighting
device;
[0011] FIG. 3B illustrates an example result of a numerical
simulation of a light distribution emitted from a lighting device
such as illustrated in FIG. 1B;
[0012] FIG. 4 is a diagram of an example vehicle headlamp system
that incorporates the lighting device of FIG. 1B; and
[0013] FIG. 5 is a diagram of another example vehicle headlamp
system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] Examples of different light illumination systems and/or
light emitting diode ("LED") implementations will be described more
fully hereinafter with reference to the accompanying drawings.
These examples are not mutually exclusive, and features found in
one example may be combined with features found in one or more
other examples to achieve additional implementations. Accordingly,
it will be understood that the examples shown in the accompanying
drawings are provided for illustrative purposes only and they are
not intended to limit the disclosure in any way. Like numbers refer
to like elements throughout.
[0015] It will be understood that, although the terms first,
second, third, etc. may be used herein to describe various
elements, these elements should not be limited by these terms.
These terms may be used to distinguish one element from another.
For example, a first element may be termed a second element and a
second element may be termed a first element without departing from
the scope of the present invention. As used herein, the term
"and/or" may include any and all combinations of one or more of the
associated listed items.
[0016] It will be understood that when an element such as a layer,
region, or substrate is referred to as being "on" or extending
"onto" another element, it may be directly on or extend directly
onto the other element or intervening elements may also be present.
In contrast, when an element is referred to as being "directly on"
or extending "directly onto" another element, there may be no
intervening elements present. It will also be understood that when
an element is referred to as being "connected" or "coupled" to
another element, it may be directly connected or coupled to the
other element and/or connected or coupled to the other element via
one or more intervening elements. In contrast, when an element is
referred to as being "directly connected" or "directly coupled" to
another element, there are no intervening elements present between
the element and the other element. It will be understood that these
terms are intended to encompass different orientations of the
element in addition to any orientation depicted in the figures.
[0017] Relative terms such as "below," "above," "upper,", "lower,"
"horizontal" or "vertical" may be used herein to describe a
relationship of one element, layer, or region to another element,
layer, or region as illustrated in the figures. It will be
understood that these terms are intended to encompass different
orientations of the device in addition to the orientation depicted
in the figures.
[0018] FIG. 1A is a top view of an example LED array 102. In the
example illustrated in FIG. 1A, the LED array 102 is an array of
emitters 120. LED arrays may be used for any application, such as
those requiring precision control of LED array emitters. Emitters
120 in the LED array 102 may be individually addressable or may be
addressable in groups/subsets.
[0019] An exploded view of a 3.times.3 portion of the LED array 102
is also shown in FIG. 1A. As shown in the 3.times.3 portion
exploded view, the LED array 102 may include emitters 120 that each
have a width w.sub.1. In embodiments, the width w.sub.1 may be
approximately 100 .mu.m or less (e.g., 40 .mu.m). Lanes 122 between
the emitters 120 may be a width, w.sub.2, wide. In embodiments, the
width w.sub.2 may be approximately 20 .mu.m or less (e.g., 5
.mu.m). The lanes 122 may provide an air gap between adjacent
emitters or may contain other material. A distance di from the
center of one emitter 120 to the center of an adjacent emitter 120
may be approximately 120 .mu.m or less (e.g., 45 .mu.m). It will be
understood that the widths and distances provided herein are
examples only and that actual widths and/or dimensions may
vary.
[0020] It will be understood that, although rectangular emitters
arranged in a symmetric matrix are shown in FIG. 1A, emitters of
any shape and arrangement may be applied to the embodiments
described herein. For example, the LED array 102 of FIG. 1A may
include over 20,000 emitters in any applicable arrangement, such as
a 200.times.100 matrix, a symmetric matrix, a non-symmetric matrix,
or the like. It will also be understood that multiple sets of
emitters, matrixes, and/or boards may be arranged in any applicable
format to implement the embodiments described herein.
[0021] As mentioned above, LED arrays, such as the LED array 102,
may include up to 20,000 or more emitters. Such arrays may have a
surface area of 90 mm.sup.2 or greater and may require significant
power to power them, such as 60 watts or more. An LED array such as
this may be referred to as a micro LED array or simply a micro LED.
A micro LED may include an array of individual emitters provided on
a substrate or may be a single silicon wafer or die divided into
segments that form the emitters. The latter type of micro LED may
be referred to as a monolithic LED.
[0022] While arrangements of light emitting elements, such as
matrix arrangements of micro-LEDs, have thus become an advantageous
choice as light sources for different applications, optical systems
for projecting or imaging the light sources onto a given target
plane, such as a road surface, may still be improved. Embodiments
described herein may provide for an improved light emitting device
that may include optical elements that may enable an improvement in
quality of an image of arrangements of light emitting elements
projected onto a target plane.
[0023] FIG. 1B is a schematic illustration of a lighting device
100. In the example illustrated in FIG. 1B, the lighting device 100
includes a first arrangement 10 of LEDs 12a, 12b and 12c and a
second arrangement 11 of LEDs 12d, 12e and 12f. It is noted that
the cross-sectional view of FIG. 1B only shows a section along LEDs
12a, 12b, 12c, 12d, 12e and 12f that are part of respective matrix
arrangements that may include additional LEDs not visible in FIG.
1B as a result of the perspective.
[0024] A first arrangement of micro-lenses 23a, 23b and 23c may be
arranged in correspondence with the first arrangement 10 of LEDs
12a, 12b and 12c, and a second arrangement of micro-lenses 23d, 23e
and 23f may be arranged in correspondence with the second
arrangement 11 of LEDs 12d, 12e and 12f. In embodiments, the
micro-lenses 23 may be optical collimation elements. Collecting
light from each of LEDs 12a, 12b and 12c, a first convex lens 21a
may be arranged in correspondence with the first arrangement 10 of
LEDs 12a, 12b and 12c. In embodiments, the first convex lens 21a
may be a magnifying optical elements that may be arranged for
generating a magnified image of the first arrangement 10 of LEDs
12a, 12b and 12c. The magnified image of the first arrangement 10
may be indicated by the dashed portion of arrow 41', which may
indicate the direction of light refracted by action of lens 21a as
compared to arrow 41, which may indicate the light path without
lens 21a. Arrows 43 and 43' illustrate the corresponding action of
lens 21b. Lens 30 may be an optical projection element and may be
arranged for collecting light emitted from the LEDs 12a, 12b, 12c,
12d, 12e and 12f of arrangements 10 and 11 and, thus, may generate
a combined image of the magnified images of the arrangements 10 and
11 generated by lenses 21a and 21b.
[0025] Thus, micro-lenses 23a, 23b, 23c, 23d, 23e and 23f may act
as pre-collimating optics for pre-collimating light emitted from
the LEDs 12a, 12b, 12c, 12d, 12e and 12f of arrangements 10 and 11.
Thereby, micro-lenses 23a, 23b, 23c, 23d, 23e and 23f may help to
reduce crosstalk between pairs of adjacent LEDs or between groups
of LEDs and may further help to increase light output efficiency of
lighting device 100.
[0026] Magnifying lenses 21a and 21b may be used to magnify the
respective arrangements 10 and 11 (i.e. the complete micro-LED
chips). As indicated by the dashed portions of arrows 41' and 43',
lenses 21a and 21b may help to fill the gap between the
arrangements 10 and 11, which may essentially correspond to the
distance between LEDs 12c and 12d. In the illustrated example, this
distance may correspond to approximately 100 .mu.m, while a gap
between pairs of LEDs within each arrangement 10 and 11 may be
approximately 20 .mu.m.
[0027] Lens 30 may collect the light emitted from all light
emitting elements 12a, 12b, 12c, 12d, 12e and 12f and, thus, may
image or project images of the arrangements 10 and 11 magnified by
lenses 21a and 21b onto a plane, such as a road surface.
[0028] In an exemplary embodiment, a light emitting element may
correspond to or include a light emitting diode (LED). In
particular, in an exemplary embodiment, a light emitting element
may correspond to or comprises a micro-LED, such as described above
with respect to FIG. 1a or as further described below. In an
exemplary embodiment, for a micro-LED, a size (e.g., an edge length
or a length of a diagonal of the LED) may be between 10 and 80
.mu.m in some embodiments, between 20 and 60 .mu.m in some
embodiments, and between 30 and 50 .mu.m in some embodiments. In
this way, individual LEDs may function as individual pixels within
the arrangements of light emitting elements. In addition, the small
size of such pixels may allow for a high pixel density, which in
turn may enable generation of sharp images producible by the
lighting device with particular high contrast. The provision of
individual arrangements of light emitting elements may also be
advantageous in terms of yield, particularly if individual chips
corresponding to such arrangement are large (for example, larger
than 1-4 mm.sup.2). In addition, use of individual arrangements or
chips may enable customization of the lighting device in accordance
with environments at which the lighting device is to be
installed.
[0029] In an exemplary embodiment, the light emitting elements of
the at least one first arrangement of light emitting elements
and/or the at least one second arrangement of light emitting
elements may be configured to be individually addressable and/or
addressable in groups. In other words, in an exemplary embodiment,
the light emitting elements may be individually connectable to a
corresponding controller for individually controlling each one of
the light emitting elements and/or groups of the light emitting
elements. In such embodiment, the lighting device may be employable
as or in connection with an automotive headlight as the possibility
to individually address/control individual pixels and/or pixel
groups may enable controlling a shape of an image generated by the
lighting device to adapt such image (e.g., a light distribution
projected onto a road) to particular situations (e.g., to driving
conditions of a car comprising the lighting device as
headlight).
[0030] In an exemplary embodiment, one, more or all of the light
emitting elements may be configured to emit light of color suitable
for an automotive headlight, such as white light. While such
embodiment may be particularly advantageous for an automotive
headlight application, in an alternative embodiment, one, more or
all of the light emitting elements may be configured to emit light
of a predefined color (e.g., green and/or blue light). For example,
in such embodiment, each of the light emitting elements may
comprise a triplet of LEDs, and one LED of the triplet may be
configured to emit red light, one LED of the triplet may be
configured to emit green light, and one LED of the triplet may be
configured to emit blue light. Thereby, in an exemplary embodiment,
each LED of the triplet may be configured to be individually
controlled (e.g., may be individually connectable to a
corresponding controller) such that an image generated by the
lighting device may be controlled not only in shape but
additionally also in color.
[0031] In an exemplary embodiment, the at least one first
arrangement of light emitting elements and/or the at least one
second arrangement of light emitting elements may correspond to or
include a matrix arrangement of the light emitting elements. In a
matrix arrangement, light emitting elements may be arranged along
respective rows and columns, forming an essentially regular
two-dimensional arrangement. In an exemplary embodiment, the at
least one first arrangement of light emitting elements and/or the
at least one second arrangement of light emitting elements may
correspond to or include a micro LED chip.
[0032] In an exemplary embodiment, a micro LED chip may correspond
to or include at least one array of individually addressable LED
junctions arranged on a common substrate. For example, the
substrate may correspond to or include a CMOS chip, and a
transistor of the CMOS chip may be arranged underneath each LED
junction a transistor. In this way, it may be possible to
individually control LEDs of the micro LED arrangement by
controlling the respective transistors. Further, in an exemplary
embodiment, individual micro LEDs or micro LED pixels may be formed
using a structured monolithic element. In an exemplary embodiment,
a small cavity may be formed around each junction/micro LED to
avoid crosstalk between the micro LEDs/pixels.
[0033] In an exemplary embodiment, the at least one second
arrangement of light emitting elements may be spatially separated
from the at least one first arrangement of light emitting elements
by a gap. Thereby, the gap may have a width that is larger than a
width of a gap separating a first light emitting element of the at
least one first arrangement and/or of the at least one second
arrangement from a second light emitting element of the at least
one first arrangement and/or of the at least one second arrangement
arranged adjacent to the first light emitting element. For example,
a gap between individual light emitting elements may be on the
order of less than a few .mu.m, less than 20 .mu.m, or less than 10
.mu.m. Further, in an exemplary embodiment, a gap between the at
least one first arrangement of light emitting elements and the at
least one second arrangement of light emitting elements may be
between 80 .mu.m and 120 .mu.m, between 90 mm and 110 .mu.m, or
about 100 .mu.m. In other words, the lighting device may include
arrangements of light emitting elements, such as micro LEDs, which
may be arranged at a particularly high density thereby allowing,
for example, generation of smooth edges of an image, such as a
headlight projected onto a road, the gaps between individual pixels
being small as compared to a gap present between individual
arrangements (e.g., chips) of light emitting elements.
[0034] In an exemplary embodiment, the at least one first
magnifying optical element may be arranged in correspondence with
the at least one first arrangement of light emitting elements, and
a center of the at least one first arrangement of light emitting
elements may be aligned with and/or arranged at an optical axis of
the at least one first magnifying optical element. Accordingly, in
an exemplary embodiment, when the at least one second magnifying
optical element is arranged in correspondence with the at least one
second arrangement of light emitting elements, a center of the at
least one second arrangement of light emitting elements may be
aligned with and/or arranged at an optical axis of the at least one
second magnifying optical element. By aligning the first and second
optical elements with the corresponding arrangements of light
emitting elements in this way, image imperfections in corresponding
magnified images of the corresponding arrangements of light
emitting elements may be minimized.
[0035] In an exemplary embodiment, the at least one first
magnifying optical element and/or the at least one second
magnifying optical element may be or include a lens element, such
as an at least partially convex lens element. Thus, the at least
one first and/or second magnifying optical element may be
configured to magnify an image of the corresponding first and/or
second arrangement of light emitting elements. In this way, the at
least one first and/or second magnifying optical element may
compensate for the gap present between the first and/or second
arrangements of light emitting elements. In other words, if, for
example, the first and/or second arrangements of light emitting
elements would be imaged using a single common projecting element
without the first and/or second magnifying optical elements, the
gap present between the first and/or second arrangement of light
emitting elements may be imaged as well thus potentially causing an
undesirable deterioration of an image of the arrangements of light
emitting elements. By employing the at least one first and the at
least one second magnifying optical elements, this gap can be
advantageously compensated for, thus advantageously improving an
image of the arrangements of light emitting elements.
[0036] In an exemplary embodiment, the at least one optical
projection element may correspond to or comprise a single lens or a
lens system arranged to collect light emitted from all light
emitting elements of the at least one first and the at least one
second arrangement of light emitting elements. In this way, the
optical projection element may be advantageously configured for
generating a combined image of the magnified images of the
arrangements of light emitting elements.
[0037] In an exemplary embodiment, the lighting device may
correspond to or be included in an automotive headlight, and the at
least one optical projection element may be arranged and configured
for projecting the combined image of the magnified image of the at
least one first arrangement of light emitting elements and the
magnified image of the at least one second arrangement of light
emitting elements onto a predefined plane, such as onto a road. In
other words, in an exemplary embodiment, the lighting device may
correspond to or be included in an automotive headlight, and a
focal distance of the at least one optical projection element may
be selected such that the combined image of the magnified image of
the at least one first arrangement of light emitting elements and
the magnified image of the at least one second arrangement of light
emitting elements may be projected onto a road.
[0038] In an exemplary embodiment, each optical collimation element
may correspond to or include a lens element arranged to collimate
light emitted from a corresponding light emitting element. In an
exemplary embodiment, each optical collimation element may
correspond to or include an at least partially convex lens element.
In an exemplary embodiment, the light emitting elements may
respectively correspond to micro LEDs, and the at least one first
arrangement of optical collimation elements and the at least one
second arrangement of optical collimation elements may respectively
correspond to respective arrangements of micro-lenses. By providing
the optical collimating elements, light emitted from individual
light emitting elements may be collimated, which may help to reduce
crosstalk between light emitting elements arranged mutually
adjacent and thereby may help to enhance contrast between images of
individual light emitting elements (e.g., pixels) of respective
arrangements.
[0039] In an exemplary embodiment, the at least one first
magnifying optical element, the at least one second magnifying
optical element and the optical collimation elements may be
integrally formed. In other words, in an exemplary embodiment, the
lighting device may further include an optical member arranged in a
path of light emitted from the light emitting elements of the first
and the second arrangement of light emitting elements. Thereby, in
an exemplary embodiment, the first magnifying optical element and
the second magnifying optical element include a face of the optical
member facing away from the first and the second arrangement of
light emitting elements. Further, in an exemplary embodiment, the
at least one first arrangement of optical collimation elements and
the at least one second arrangement of optical collimation elements
may include a face of the optical member facing the first and the
second arrangement of light emitting elements.
[0040] In other words, in an exemplary embodiment, the at least one
first and second magnifying optical elements and the optical
collimation elements may be formed from respective, mutually
opposing, faces of the optical member. In this way, a particularly
advantageous compact design of the light emitting element may be
enabled. Thereby, in an exemplary embodiment, the at least one
first magnifying optical element, the at least one second
magnifying optical element, one, more or each of the optical
collimation elements and/or the optical member may be formed from
or include glass or silicone. Using glass may be particularly
advantageous in that glass may enable forming corresponding
elements of high precision while it may withstand high temperatures
and may thus be placed in close vicinity of the arrangements of
light emitting elements, which, in an exemplary embodiment, may
correspond to high power LEDs to be used for automotive headlight
applications. Further, use of silicone may be advantageous in that
a less complex production process may be employed for producing the
respective component.
[0041] Thus, in an exemplary embodiment, respective arrangements of
pre-collimating micro-lenses may be aligned with corresponding
arrangements of micro-LED pixels. A combination with magnifying
lenses aligned with respective arrangements of the micro-LEDs may
allow, on the one hand, for compensating for the gap present
between respective arrangements of micro-LEDs, and, on the other
hand, may contribute to an improved light output efficiency of the
overall system. Thereby, the arrangements of pre-collimating
micro-lenses facing respective micro-LED pixels may enable an
increase in light output efficiency and enable a reduction in
crosstalk between respective pixels and/or between pixel groups.
The complete assembly may be imaged or projected by the at least
one optical projection element (e.g., a single lens or lens
system). In an exemplary embodiment, the focus of the at least one
optical projection element may be in a plane defined by the at
least one first arrangement of light emitting elements and/or by
the at least one second arrangement of light emitting elements
(e.g., of the .mu.-LED arrangements). In this way, an advantageous
imaging/projecting of the magnified images of the respective
arrangements of light emitting elements may be enabled.
[0042] In an exemplary embodiment, the lighting system may
correspond to or include an automotive headlight system and the
controller may correspond to or include control electronics (e.g.,
of a car) for controlling light emitting elements of the at least
one first and of the at least one second arrangements of light
emitting elements. In an alternative exemplary embodiment, the
lighting system may correspond to or include a light projector
system, and the controller may correspond to or include control
electronics (e.g., of a projector) for controlling light emitting
elements of the at least one first and of the at least one second
arrangements of light emitting elements.
[0043] FIG. 2 illustrates three arrangements of micro-lenses 23 and
magnifying lenses 21a, 21b and 21c as shown in FIG. 1. As can be
taken from FIG. 2, the magnifying lenses 21a, 21b and 21c and the
micro-lenses 23 may be integrally formed. In other words, the
second magnifying lenses 21a, 21b and 21c may be formed from a face
of an optical member while micro-lenses 23 may be formed from an
opposing face of the optical member. As mentioned above, in
particular where lighting device 100 is used as light source for an
automotive headlight where LEDs 12a, 12b, 12c, 12d, 12e and 12f
correspond to high power white light LEDs, forming the optical
member from a glass material may be advantageous in terms of a
corresponding capability to withstand heat generated by the LEDs,
and the corresponding optical arrangements may be placed in close
proximity to the LEDs.
[0044] FIG. 3A illustrates a result of a numerical simulation of a
light distribution emitted from a lighting device not employing any
magnifying lens corresponding to magnifying lenses 21a and 21b of
FIG. 1. The shown light distribution includes three images 50,
including images 51 (only 1 labeled in the central image 50 of FIG.
3A) of LEDs of respective 6.times.6 matrix arrangements of LEDs.
The light distribution of FIG. 3A is obtained by simulating the
effect of pre-collimating lenses corresponding to lenses 23a, 23b,
23c, 23d, 23e and 23f of FIG. 1 and arranged in correspondence with
each LED of each one of the 6.times.6 arrangement of LEDs and of a
projection lens corresponding to lens 30 of FIG. 1 arranged for
collecting the light from each of the three 6.times.6 matrix
arrangements of LEDs. As can be taken from FIG. 3A, gaps present
between the respective 6.times.6 matrix arrangements of LEDs may be
imaged as gaps 53 in the light distribution of FIG. 3A, undesirably
interrupting and thereby deteriorating the resulting light
distribution (e.g., the projected image of the respective LED
matrix arrangements).
[0045] FIG. 3B illustrates a result of a numerical simulation of a
light distribution emitted from a lighting device further employing
magnifying lenses corresponding to magnifying lenses 21a and 21b of
FIG. 1. Again, the shown light distribution includes three images
50, including images 51 (only 1 labeled in the central image 50 of
FIG. 3B) of LEDs of respective 6.times.6 matrix arrangements of
LEDs. However, as opposed to the case of FIG. 3A, as a result of
the magnifying lenses (the magnifying optical elements), a gap
present between the respective 6.times.6 matrix arrangements of
LEDs may not be imaged such that the deteriorating interruption of
the light distribution shown in FIG. 3A is no longer present in the
light distribution shown in FIG. 3B.
[0046] It is noted that a central light emitting element of each
6.times.6 matrix arrangement of LEDs imaged in FIGS. 3A and 3B is
turned off, thus illustrating the capability to individually
address and control individual LEDs.
[0047] FIG. 4 is a diagram of an example vehicle headlamp system
300 that may incorporate the lighting device 100 of FIG. 1B. The
example vehicle headlamp system 300 illustrated in FIG. 3 includes
power lines 302, a data bus 304, an input filter and protection
module 306, a bus transceiver 308, a sensor module 310, an LED
direct current to direct current (DC/DC) module 312, a logic
low-dropout (LDO) module 314, a micro-controller 316 and an active
head lamp 318. In embodiments, the active head lamp 318 may include
a lighting device, such as the lighting device 100 of FIG. 1B.
[0048] The power lines 302 may have inputs that receive power from
a vehicle, and the data bus 304 may have inputs/outputs over which
data may be exchanged between the vehicle and the vehicle headlamp
system 300. For example, the vehicle headlamp system 300 may
receive instructions from other locations in the vehicle, such as
instructions to turn on turn signaling or turn on headlamps, and
may send feedback to other locations in the vehicle if desired. The
sensor module 310 may be communicatively coupled to the data bus
304 and may provide additional data to the vehicle headlamp system
300 or other locations in the vehicle related to, for example,
environmental conditions (e.g., time of day, rain, fog, or ambient
light levels), vehicle state (e.g., parked, in-motion, speed of
motion, or direction of motion), and presence/position of other
objects (e.g., vehicles or pedestrians). A headlamp controller that
is separate from any vehicle controller communicatively coupled to
the vehicle data bus may also be included in the vehicle headlamp
system 300. In FIG. 4, the headlamp controller may be a
micro-controller, such as micro-controller (.mu.c) 316. The
micro-controller 316 may be communicatively coupled to the data bus
304.
[0049] The input filter and protection module 306 may be
electrically coupled to the power lines 302 and may, for example,
support various filters to reduce conducted emissions and provide
power immunity. Additionally, the input filter and protection
module 306 may provide electrostatic discharge (ESD) protection,
load-dump protection, alternator field decay protection, and/or
reverse polarity protection.
[0050] The LED DC/DC module 312 may be coupled between the filter
and protection module 306 and the active headlamp 318 to receive
filtered power and provide a drive current to power LEDs in the LED
array in the active headlamp 318. The LED DC/DC module 312 may have
an input voltage between 7 and 18 volts with a nominal voltage of
approximately 13.2 volts and an output voltage that may be slightly
higher (e.g., 0.3 volts) than a maximum voltage for the LED array
(e.g., as determined by factor or local calibration and operating
condition adjustments due to load, temperature or other
factors).
[0051] The logic LDO module 314 may be coupled to the the input
filter and protection module 306 to receive the filtered power. The
logic LDO module 314 may also be coupled to the micro-controller
314 and the active headlamp 318 to provide power to the
micro-controller 314 and/or the silicon backplane (e.g., CMOS
logic) in the active headlamp 318.
[0052] The bus transceiver 308 may have, for example, a universal
asynchronous receiver transmitter (UART) or serial peripheral
interface (SPI) interface and may be coupled to the
micro-controller 316. The micro-controller 316 may translate
vehicle input based on, or including, data from the sensor module
310. The translated vehicle input may include a video signal that
is transferrable to an image buffer in the active headlamp module
318. In addition, the micro-controller 316 may load default image
frames and test for open/short pixels during startup. In
embodiments, an SPI interface may load an image buffer in CMOS.
Image frames may be full frame, differential or partial frames.
Other features of micro-controller 316 may include control
interface monitoring of CMOS status, including die temperature, as
well as logic LDO output. In embodiments, LED DC/DC output may be
dynamically controlled to minimize headroom. In addition to
providing image frame data, other headlamp functions, such as
complementary use in conjunction with side marker or turn signal
lights, and/or activation of daytime running lights, may also be
controlled.
[0053] FIG. 5 is a diagram of another example vehicle headlamp
system 400. The example vehicle headlamp system 400 illustrated in
FIG. 5 includes an application platform 402, two lighting devices
406 and 408, and optics 410 and 412. The two lighting devices 406
and 408 may be lighting devices, such as the lighting device 100 of
FIG. 1B, or may include the lighting device 100 plus some of all of
the other modules in the vehicle headlamp system 300 of FIG. 4. In
the latter embodiment, the lighting devices 406 and 408 may be
vehicle headlamp sub-systems.
[0054] The lighting device 408 may emit light beams 414 (shown
between arrows 414a and 414b in FIG. 4). The lighting device 406
may emit light beams 416 (shown between arrows 416a and 416b in
FIG. 4). In the embodiment shown in FIG. 4, a secondary optic 410
is adjacent the lighting device 408, and the light emitted from the
lighting device 408 passes through the secondary optic 410.
Similarly, a secondary optic 412 is adjacent the lighting device
412, and the light emitted from the lighting device 412 passes
through the secondary optic 412. In alternative embodiments, no
secondary optics 410/412 are provided in the vehicle headlamp
system.
[0055] The application platform 402 may provide power and/or data
to the lighting devices 406 and/or 408 via lines 404, which may
include one or more or a portion of the power lines 302 and the
data bus 304 of FIG. 4. One or more sensors (which may be the
sensors in the system 300 or other additional sensors) may be
internal or external to the housing of the application platform
402. Alternatively or in addition, as shown in the example lighting
device 300 of FIG. 4, each lighting device 408 and 406 may include
its own sensor module, connectivity and control module, power
module, and/or LED array.
[0056] In embodiments, the vehicle headlamp system 400 may
represent an automobile with steerable light beams where LEDs may
be selectively activated to provide steerable light. For example,
an array of LEDs (e.g., the LED array 102) may be used to define or
project a shape or pattern or illuminate only selected sections of
a roadway. In an example embodiment, infrared cameras or detector
pixels within lighting devices 406 and 408 may be sensors (e.g.,
similar to sensors in the sensor module 310 of FIG. 4) that
identify portions of a scene (e.g., roadway or pedestrian crossing)
that require illumination.
* * * * *